The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 3.4 M. What is the rate constant for this reaction?

0.88m hope i am correct : )

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.